From the Guidelines
The post-operative state promotes atelectasis through several mechanisms, including pain, anesthesia, supine positioning, immobility, surgical manipulation, and post-operative pain medications, which combine to create a perfect environment for alveolar collapse. These factors can lead to decreased functional residual capacity, increased heterogeneity of lung expansion, cyclic lung overstress, and increased driving pressure, ultimately resulting in atelectasis and postoperative pulmonary complications 1. The use of nasogastric tubes can also increase the risk of aspiration and subsequent atelectasis, although selective use of nasogastric tubes has been shown to reduce the rate of pneumonia and atelectasis compared to routine use 1. Prevention strategies, such as early mobilization, incentive spirometry, adequate pain control with multimodal approaches, and positive pressure ventilation techniques like CPAP, can help maintain lung expansion and prevent the complications associated with atelectasis 1. It is essential to employ strategies to reduce postoperative pulmonary complications in patients who are at high risk after clinical risk stratification, taking into account patient-related risk factors, such as chronic obstructive pulmonary disease, age, ASA class, functional dependence, and congestive heart failure, as well as procedure-related risk factors, including prolonged surgery, abdominal surgery, thoracic surgery, and emergency surgery 1. Incentive spirometry and deep breathing exercises have been shown to be effective in reducing postoperative pulmonary complications, and should be used in conjunction with other prevention strategies to minimize the risk of atelectasis and other pulmonary complications 1.
From the Research
Postoperative State and Atelectasis
The postoperative state can promote atelectasis due to various factors, including:
- Anaesthesia-induced lung collapse, which can persist for several days after surgery 2
- Use of high oxygen concentration during induction and maintenance of anaesthesia, leading to absorption atelectasis behind closed airways 2
- Loss of muscle tone and fall in functional residual capacity caused by anaesthetics 2
- Compression of lung tissue and loss of surfactant or surfactant function 2
Mechanisms of Atelectasis
Atelectasis can occur due to:
- Absorption atelectasis, where the use of high oxygen concentration leads to the absorption of oxygen from the alveoli, causing the lung tissue to collapse 2
- Compression atelectasis, where the lung tissue is compressed, leading to the collapse of the alveoli 3
- The use of mechanical ventilators during surgery, which can lead to the development of atelectasis 3
Prevention and Treatment of Atelectasis
Prevention and treatment of atelectasis can be achieved through:
- Incentive spirometry, which has been shown to be effective in preventing postoperative pulmonary complications, including atelectasis 4, 5, 6
- Deep breathing exercises, which can help to improve lung function and prevent atelectasis 6
- Recruitment maneuvers, which involve the use of positive end-expiratory pressure (PEEP) to reopen collapsed lung tissue 4
- Ventilation with moderate fractions of inspired oxygen (FIO2) to prevent the reappearance of atelectasis 2